ERGO (Ergothioneine) is naturally occurring antioxidant derived from the diet and abundantly contained in golden oyster mushroom (Pleurotus cornucopiae var. citrinopileatus. It is hydrophilic and membrane impermeable, but is well absorbed from the gastrointestinal tract due to the presence of a specific carrier‐mediated transport system, carnitine/organic cation transporter OCTN1/SLC22A4, essential for the beta-oxidation of fatty acids. Numerous in vitro assays have demonstrated the antioxidant and cytoprotective capabilities of ERGO against a wide range of cellular stressors, but an antioxidant role has yet to be fully verified in vivo. Nevertheless, the accumulation, tissue distribution, and scavenging properties, all highlight the potential for EGT to function as a physiological antioxidant. Because ERGO is highly distributed into the brain after oral ingestion, OCTN1 may contribute to the alleviation of oxidative stress and promotion of neuronal differentiation via the uptake of ERGO in the brain, perhaps abating symptoms of neurological disorders.